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| -rw-r--r-- | changelog.d/15498.doc | 1 | ||||
| -rw-r--r-- | docs/development/database_schema.md | 34 |
2 files changed, 2 insertions, 33 deletions
diff --git a/changelog.d/15498.doc b/changelog.d/15498.doc new file mode 100644 index 0000000000..78715b8a3e --- /dev/null +++ b/changelog.d/15498.doc @@ -0,0 +1 @@ +Update outdated development docs that mention restrictions in versions of SQLite that we no longer support. diff --git a/docs/development/database_schema.md b/docs/development/database_schema.md index 29945c264e..e231be21dd 100644 --- a/docs/development/database_schema.md +++ b/docs/development/database_schema.md @@ -155,43 +155,11 @@ def run_upgrade( Boolean columns require special treatment, since SQLite treats booleans the same as integers. -There are three separate aspects to this: - - * Any new boolean column must be added to the `BOOLEAN_COLUMNS` list in +Any new boolean column must be added to the `BOOLEAN_COLUMNS` list in `synapse/_scripts/synapse_port_db.py`. This tells the port script to cast the integer value from SQLite to a boolean before writing the value to the postgres database. - * Before SQLite 3.23, `TRUE` and `FALSE` were not recognised as constants by - SQLite, and the `IS [NOT] TRUE`/`IS [NOT] FALSE` operators were not - supported. This makes it necessary to avoid using `TRUE` and `FALSE` - constants in SQL commands. - - For example, to insert a `TRUE` value into the database, write: - - ```python - txn.execute("INSERT INTO tbl(col) VALUES (?)", (True, )) - ``` - - * Default values for new boolean columns present a particular - difficulty. Generally it is best to create separate schema files for - Postgres and SQLite. For example: - - ```sql - # in 00delta.sql.postgres: - ALTER TABLE tbl ADD COLUMN col BOOLEAN DEFAULT FALSE; - ``` - - ```sql - # in 00delta.sql.sqlite: - ALTER TABLE tbl ADD COLUMN col BOOLEAN DEFAULT 0; - ``` - - Note that there is a particularly insidious failure mode here: the Postgres - flavour will be accepted by SQLite 3.22, but will give a column whose - default value is the **string** `"FALSE"` - which, when cast back to a boolean - in Python, evaluates to `True`. - ## `event_id` global uniqueness |